In many applications of float valves, and particularly where such valves are used in evaporative coolers, there is a need to adjust the height of water level, and this is normally achieved by adjusting the effective height of a float with respect to its valve. If a valve arm is formed from metal this is sometimes achieved by bending the metal, but such a method is not available if the valve arm is formed from plastics material.
The main object of this invention is to provide improvements whereby float level can be easily adjusted, without the need for expensive adjustment means.